Endoscopic therapy for gastric stromal tumors originating from the muscularis propria

An artificial intelligence model utilizing endoscopic ultrasonography for differentiating small and micro gastric stromal tumors from gastric leiomyomas

BACKGROUND

Gastric stromal tumors (GSTs) and gastric leiomyomas (GLs) represent the primary subtypes of gastric submucosal tumors (SMTs) characterized by distinct biological characteristics and treatment modalities. The accurate differentiation between GSTs and GLs poses a significant clinical challenge. Recent advancements in artificial intelligence (AI) leveraging endoscopic ultrasonography (EUS) have demonstrated promising results in the categorization of larger-diameter SMTs (> 2.0 cm). However, the diagnostic capacity of AI models for micro-diameter SMTs (< 1.0 cm) remains uncertain due to limited imaging features. This study seeks to develop a specialized diagnostic model utilizing EUS images to differentiate small and micro GSTs from GLs effectively.

METHODS

In this study, a dataset comprising 358 EUS images of GSTs or GLs was utilized for training the EUS-AI model. Subsequently, 216 EUS images were allocated for validation purposes, with 159 images in validation set 1 (micro SMTs: tumor diameter < 1.0 cm) and 216 images in validation set 2 (small SMTs: tumor diameter < 2.0 cm). The diagnostic performance of the EUS-AI model for individual tumors was assessed by consolidating the diagnostic outcomes of the corresponding images. Comparative analyses were conducted between the diagnostic outcomes of endoscopists, clinical signatures, and those of the EUS-AI models.

RESULTS

The EUS-AI models were developed using DenseNet201, ResNet50, and VGG19 architectures. Among the three models, the ResNet50 model demonstrated superior performance on EUS images, achieving area under the curve (AUC) values of 0.938, 0.832, and 0.841 in the training set, validation set 1, and validation set 2, respectively. By combining predictions from multiple images for each tumor, the diagnostic efficacy of ResNet50 was further enhanced, resulting in AUCs of 0.994, 0.911, and 0.915 in the aforementioned sets. In comparison, both clinical signatures and endoscopists exhibited notably lower AUC values than those obtained with the EUS-AI model.

CONCLUSIONS

The EUS-AI model utilizing ResNet50 architecture effectively discriminates between micro GSTs and GLs from both image-centric and tumor-centric perspectives. Demonstrating superior diagnostic efficiency compared to clinical models and assessments by endoscopists, the EUS-AI model serves as a valuable tool for clinicians in precisely distinguishing small and micro GSTs from GLs before surgery.

Endoscopic submucosal excavation for gastric muscularis propria tumours less than 10 mm in diameter: What are the risk factors responsible for perforation?

OBJECTIVE

To explore the risk factors for perforation during endoscopic submucosal excavation (ESE) for gastric muscularis propria tumours less than 10 mm in diameter. This study provides clinical guidance for preventing the occurrence of intraoperative adverse events.

METHODS

Samples of gastric muscularis propria tumours less than 10 mm in diameter were removed via ESE at Shenzhen Second People's Hospital and were collected from June 2023 to August 2024. The general clinical characteristics of the patients, location, size, growth pattern, and pathology of the tumours, operation time, resection time, perforation incidence and bleeding incidence were analysed, and logistic regression was used to calculate the risk factors for perforation and bleeding.

RESULTS

A total of 102 patients were included in this study. The tumours were successfully removed from all patients. The mean age was 52.28 ± 11.84 years. There were 34 (33.33%) males. The mean size was 6.96 ± 1.82 mm. 89 (87.25%) tumours exhibited an intraluminal growth pattern. In total, 79 (77.45%) tumours were in the gastric body, and 23 (22.55%) tumours were in the gastric fundus. The mean operation time was 35.26 ± 23.15 min, and the mean resection time was 27.88 ± 21.77 min. A total of 55 (53.92%) tumours were leiomyoma, and 43 (42.16%) tumours were GIST. There were 4 (3.92%) tumours classified as other lesions. 41 (40.20%) patients experienced intraoperative bleeding, all of which had minor bleeding and successful haemostasis under endoscopy.There were 27 (26.47%) concurrent perforation, of which,24(88.89%) were diagnosed as GIST, and 3(11.11%) were diagnosed as leiomyoma. All perforations were successfully managed with an endoscopic suture. According to the multivariate regression analysis, a pathologic diagnosis was a risk factor for perforation. When the pathological diagnosis is GIST, the risk of perforation increases (PE = 18.632, 95% CI 4.571 ~ 75.941; p < 0.001). Gender,age,tumor size, growth pattern, location, and resection time were not found to be risk factors for perforation.all of observed factors were not the risk factors for bleeding.

CONCLUSION

ESE is an effective removal method for gastric muscularis propria tumours less than 10 mm in diameter.Intraoperative bleeding and perforation are common.However, these complications are controllable.GIST is an independent risk factor for the perforation.When the tumour is diagnosed as a GIST, the incidence of perforation is significantly increased.

Endoscopic semi-blunt dissection technique is safe and effective for treating gastric submucosal tumors from the muscularis propria

BACKGROUND

Needle knives are the most commonly used instrument during endoscopic treatment for gastric submucosal tumors (SMTs). The conventional resection method involves fully extending the needle-shaped knife head, which allows it to more easily penetrate the muscularis propria while stripping the muscle layer of the tumor. We propose a semi-blunt dissection method that can effectively reduce damage to the muscularis propria.

METHODS

A total of 113 patients who underwent endoscopic resection of gastric SMTs originating from the muscularis propria were retrospectively analyzed. The conventional method consisted of 73 patients; The other group consisted of 40 patients underwent the semi-blunt dissection method.

RESULTS

There was no significant difference between the two groups in age, sex, or lesion location. The intraoperative operational variable, the maximum diameter of gastric muscularis propria damage, was significantly greater in conventional method group than the other group (1.06 ± 0.48 cm vs. 0.46 ± 0.09 cm, p < 0.001). There was also no significant difference between the two groups in terms of histological diagnosis, postoperative complications and the percentage of histologically positive resection margins.

CONCLUSION

The semi-blunt dissection method has certain advantages in the endoscopic resection of gastric tumors originating from the muscularis propria, including a small extent of gastric muscularis propria damage and a shorter postoperative hospital stay.

Postoperative encapsulated hemoperitoneum in a patient with gastric stromal tumor treated by exposed endoscopic full-thickness resection: A case report

BACKGROUND

Gastric stromal tumors, originating from mesenchymal tissues, are one of the most common tumors of the digestive tract. For stromal tumors originating from the muscularis propria, compared with conventional endoscopic submucosal dissection (ESD), endoscopic full-thickness resection (EFTR) can remove deep lesions and digestive tract wall tumors completely. However, this technique has major limitations such as perforation, postoperative bleeding, and post-polypectomy syndrome. Herein, we report a case of postoperative serous surface bleeding which formed an encapsulated hemoperitoneum in a patient with gastric stromal tumor that was treated with exposed EFTR. Feasible treatment options to address this complication are described.

CASE SUMMARY

A 47-year-old male patient had a hemispherical protrusion found during gastric endoscopic ultrasonography, located at the upper gastric curvature adjacent to the stomach fundus, with a smooth surface mucosa and poor mobility. The lesion was 19.3 mm × 16.1 mm in size and originated from the fourth ultrasound layer. Computed tomography (CT) revealed no significant evidence of lymph node enlargement or distant metastasis. Using conventional ESD technology for mucosal pre-resection, exposed EFTR was performed to resect the intact tumor in order to achieve a definitive histopathological diagnosis. Based on its morphology and immunohistochemical expression of CD117 and DOG-1, the lesion was proven to be consistent with a gastric stromal tumor. Six days after exposed EFTR, CT showed a large amount of encapsulated fluid and gas accumulation around the stomach. In addition, gastroscopy suggested intracavitary bleeding and abdominal puncture drainage indicated serosal bleeding. Based on these findings, the patient was diagnosed with serosal bleeding resulting in encapsulated abdominal hemorrhage after exposed EFTR for a gastric stromal tumor. The patient received combined treatments, such as hemostasis under gastroscopy, gastrointestinal decompression, and abdominal drainage. All examinations were normal within six months of follow-up.

CONCLUSION

This patient developed serous surface bleeding in the gastric cavity following exposed EFTR. Serosal bleeding resulting in an encapsulated hemoperitoneum is rare in clinical practice. The combined treatment may replace certain surgical techniques.

Risk factors of perforation in gastric stromal tumors during endoscopic resection: a retrospective case-control study

BACKGROUND AND AIMS

Perforation is a common complication during endoscopic resection (ER) of gastric gastrointestinal stromal tumors (gGISTs) associated with secondary infections, sepsis, hospitalization time and cost. However, the risk factors of perforation remain controversial. This study aimed to investigate the risk factors for perforation during ER of gGISTs.

METHODS

This retrospective case-control study included consecutive patients with gGISTs who underwent ER between June 2009 and November 2021 at the Nanjing Drum Tower Hospital. Univariate and multivariate analyses were performed to investigate the risk factors for perforation. Sensitivity analyses with propensity scoring (PS) were performed to evaluate the stability of the independent effects.

RESULTS

In total, 422 patients with gGISTs were included. The following factors were associated with perforation during ER: in the non-intraluminal growth patterns (all confounders adjusted odds ratio [aOR]: 5.39, 95% CI 2.99-9.72, P < 0.001), in the gastric fundus (aOR 2.25, 95% CI 1.40-3.60, P = 0.007), sized ≥ 2 cm (aOR 1.70, 95% CI 1.04-2.77, P = 0.035), in the lesser curvature (aOR 0.12, 95% CI 0.05-0.27, P < 0.001), and in the gastric cardia (aOR 0.13, 95% CI 0.04-0.50, P = 0.003). The PS analysis confirmed the stable independent effects of these identified risk factors.

CONCLUSIONS

ERs of gGISTs in non-intraluminal growth patterns, in the gastric fundus, and with larger tumor size were independent risk factors for perforation. While tumors in the lesser curvature or gastric cardia were independent protective factor for perforation.

Clinical Efficacy and Safety of Endoscopic Treatment of Gastrointestinal Stromal Tumors in the Stomach

Background/Aims

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the stomach. We evaluated the clinical outcomes of endoscopic treatment for gastric GISTs.

Methods

This is a single center, retrospective study that enrolled 135 cases of gastric subepithelial tumors (SETs) resected by endoscopic procedures and confirmed as GISTs by histopathology from March 2005 to July 2019. The immediate and long-term clinical outcomes were analyzed retrospectively.

Results

The mean patient age was 57.9 years, and the mean tumor size was 2.1 cm. Of the tumors, 43.0% were located in the body, followed by the fundus (26.7%) and cardia (17.0%). Most tumors (85.2%) were resected by endoscopic submucosal dissection, followed by endoscopic mucosal resection (6.7%), submucosal tunneling endoscopic resection (5.9%), and endoscopic full-thickness resection (2.2%). Macroperforation occurred in 4.4% and microperforation in 6.7% of the cases. The R0 resection rate was 15.6%. However, the rate of complete resection by the endoscopic view was 90.4%, of which 54.8% of cases were in the very-low-risk group, followed by the low-risk group (28.1%), intermediate-risk group (11.9%), and high-risk group (5.2%). During 36.5 months of follow-up, recurrence was found in four (3.4%) of the 118 patients who were monitored for more than 6 months (low-risk group, 1/37 [2.7%]; intermediate-risk group, 2/11 [18.2%]; high-risk group, 1/6 [16.7%]).

Conclusions

Endoscopic treatment of a GIST appears to be a feasible procedure in selected cases. However, additional surgery should be considered if the pathologic results correspond to intermediate- or high-risk groups.

Factors predicting technical difficulties during endoscopic submucosal excavation for gastric submucosal tumor

OBJECTIVE

Endoscopic submucosal excavation (ESE) has been established as an effective method for removal of gastric submucosal tumors (SMTs). The aim of the present study was to explore risk factors for technical difficulties in ESE.

METHODS

In this retrospective study, we collected clinical data from patients who underwent ESE for gastric SMTs. Difficult ESE was defined as a procedure time ≥90 minutes, piecemeal resection, and/or occurrence of major adverse events. Univariate and multivariate analyses were performed to explore the risk factors for a difficult ESE.

RESULTS

ESE was successfully performed in 96.5% (195/202) of patients from April 2011 to December 2019. The average tumor size was 17.41 mm, and en bloc resection was achieved in 97.4% of patients (190/195). Five patients (2.56%, 5/195) had complications, including two with delayed bleeding, two with fever, and one with chest pain accompanying ST-T changes in an electrocardiogram. Twenty-four patients (11.88%, 24/202) had a difficult ESE. Logistic analysis showed that outgrowth behavior and an inexperienced surgeon were risk factors for a difficult ESE.

CONCLUSION

ESE may be safe and effective to treat patients with gastric SMTs. Outgrowth behavior and an inexperienced surgeon were risk factors for a difficult ESE.

Optimal Endoscopic Resection Technique for Selected Gastric GISTs. The Endoscopic Suturing System Combined with ESD-a New Alternative?

Background and Study Aim: In terms of therapeutic management, gastrointestinal stromal tumors (GISTs) seem to be the most difficult group of subepithelial gastrointestinal lesions (SELs). Despite various treatment option, choice of optimal management remains a dilemma in daily practice. Our aim was to evaluate a new hybrid resection technique of gastric GISTs type III as a modality of endoscopic full-thickness resection. Methods: Three males and one female (mean age of 68) were qualified for the procedure. Endoscopic full-thickness resections consisted of the endoscopic resection combined with suturing by Apollo OverStitch System. The main inclusion criterium was a complete diagnosis of GISTs (computed tomography (CT), endoscopic ultrasound (EUS), fine-needle biopsy (FNB)) with the evaluation of the tumor features, especially, the location in the gastric wall. All of the tumors were type III with a diameter between 20–40 mm. The lesions were located in the corpus (1), antrum (1) and between gastric body and fundus (2). All procedures were performed in 2019. Results: The technical and therapeutic success rate was 100% and the mean resection time 107.5 min. Neither intra- nor postprocedural complications were observed. In all four cases, R0 resection was achieved. Histopathologic assessment confirmed GIST with <5mitose/50HPF in all of the tumors, with very low risk. Conclusion: Based on our outcomes, endoscopic resection combined with the sewing by Apollo OverStitch of gastric GISTs type III, with the diameter between 20–40 mm, seems to be an effective therapeutic option with a good safety profile, however further studies with a larger treatment group are needed.

Suitability and efficacy of submucosal tunneling endoscopic resection for the treatment of giant leiomyoma in the middle and lower esophagus

Esophageal leiomyoma constitutes the majority of benign esophageal tumors, and detection rates are increasing. Submucosal tunneling endoscopic resection (STER) is a new technique developed to treat patients with esophageal leiomyoma, but the viability of STER for treating giant esophageal leiomyoma (GEL), particularly in the lower esophagus and close to the cardia, requires verification. This retrospective study assessed the efficacy of STER for the treatment of GEL. From January 2016 to April 2018, 10 patients underwent STER and endoscopic ultrasonography at the Endoscopic Center in Jianyang People's Hospital, and were found with histopathologically confirmed esophageal leiomyoma >3 cm. These cases were reviewed for successful excision, postoperative complications, and tumor recurrence. Seven of the 10 patients were men. Diagnoses of esophageal leiomyoma and negative resection margins were postoperatively confirmed in all 10 patients. All GELs were successfully excised. The mean operative time was 70.3 min (range, 28-100 min). The largest resected tumor was 14 cm. No adverse event occurred, and no delayed bleeding or associated infection. The patients were given postoperative conservative treatment and discharged. The mean hospitalization was 5.8 days (range, 3-10 d). During the scheduled follow-ups at 1, 3, 6, and 12 months post-STER, patients reported neither abdominal discomfort nor pain. No recurrent esophageal leiomyoma was detected at the follow-ups 3 months or longer following STER. STER is an effective and safe endoscopic resection technique for treating patients with GEL. Men may be at greater risk than women of developing GEL.

Treatment recommendations for small gastric gastrointestinal stromal tumors: positive endoscopic resection

Objectives: To evaluate the safety and efficacy of endoscopic resection and discuss the treatment strategy of small gastric gastrointestinal stromal tumors (GISTs) less than 2 cm. Material and methods: The data of 713 patients, who underwent endoscopic submucosal dissection (ESD) for gastric submucosal tumors (SMTs), were retrospectively analyzed. We investigated the clinicopathological features and analyzed the risk potential of small gastric GISTs, and documented therapeutic and follow-up outcomes. We also compared the follow-up results between operated patients and 58 patients who were suspected of small gastric GISTs and underwent regular surveillance under endoscopic ultrasound (EUS) in the same period. Results: GISTs were the most common gastric SMTs (289 cases, 40.5%), of which small GISTs were found in 250 cases. The mitotic index was less than 5 in all cases. However, 122 out of 250 cases (48.8%) had adverse factors under EUS, which were related to tumor size (p < .01). ESD was successfully performed in all patients, and no serious complication or perioperative death occurred. The follow-up period for 42.07 ± 22.49 months revealed improvement of symptoms in 80.2% patients and showed no recurrence or metastasis. Of the 58 patients selected for EUS surveillance, 48 (82.8%) presented with gastrointestinal symptoms and 41 out of 48 (85.4%) were not relieved during follow-up and 16 (27.6%) with severe psychological problems. Conclusions: ESD is a safe and effective treatment for small GISTs, which helps to confirm the diagnosis, improve symptoms and reduce the psychological pressure. Thus, we recommend endoscopic resection is a good option for small gastric GISTs once diagnosed.

Endoscopic full-thickness resection for gastric gastrointestinal stromal tumor originating from the muscularis propria

SUMMARY OBJECTIVE: This study retrospectively reviewed 46 cases of gastric gastrointestinal stromal tumors treated by endoluminal endoscopic full-thickness resection (EFR) microsurgery in our gastrointestinal endoscopy center. We aimed to evaluate the EFR for the treatment of gastric gastrointestinal stromal tumors originating from the muscularis propria. METHODS: A total of 46 patients with gastric gastrointestinal stromal tumors originated from the muscularis propria layer from January 2012 to June 2015 were treated with EFR. The patients were followed up with gastroscope and computed tomography (CT) for evaluation of therapeutic effect and safety. RESULTS: EFR was successfully accomplished to remove all tumors in 46 patients. The mean procedure time was 82.5±39.8min (56-188min). Except in 3 leiomyomas, pathological examination confirmed gastrointestinal stromal tumor (GIST) in 43 cases. None of the patients had occurred bleeding, peritonitis and other complications after EFR. Thereafter, all patients were followed up with gastro-scope after 1, 6,12 months. CONCLUSIONS: EFR is effective and safe for patients with gastric gastrointestinal stromal tumors originated from muscularis propria layer and has the advantage of less invasive treatment and higher tumor resection rate. It should be considered for further application.

Endoscopic resection of gastric gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract, and about 60% of them are found in the stomach. With the widespread application of endoscopy and endoscopic ultrasonography (EUS), more and more gastric GISTs are being found in an early stage (with a relative small diameter and no metastasis), giving the chance of complete resection. Endoscopic resection such as endoscopic band ligation (EBL), endoscopic submucosal dissection (ESD), endoscopic submucosal excavation (ESE), endoscopic full-thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER), is a minimally invasive method compared with the conventional surgical approaches (open or laparoscopic), and has been demonstrated to be safe and effective for treating gastric GISTs. This review summarizes the recent advances on endoscopic resection of gastric GISTs, aiming to provide a rational management strategy for gastric GISTs.

Effectiveness and safety of endoscopic resection for gastric GISTs: a systematic review

AIMS

To evaluate the effectiveness and safety of endoscopic resection for gastric gastrointestinal stromal tumors (GISTs).

MATERIAL AND METHODS

The effectiveness and safety of endoscopic resection were mainly assessed by complete resection rate, postoperative adverse event rate, and recurrence rate. Moreover, a comparison of endoscopic with laparoscopic resection for gastric GISTs was made through weighted mean difference by STATA 12.0 with regard to operation time, blood loss, and length of stay after including patients who underwent endoscopic or laparoscopic resection for gastric GISTs in the comparative studies.

RESULTS

Eleven studies investigating endoscopic resection for GISTs were included. For stromal tumors <2 cm in average diameters the pooled rates of complete resection, postoperative adverse events and recurrence were 0.97, 0.08, and 0.03, respectively. Only five retrospective studies directly compared endoscopic with laparoscopic resection for gastric GISTs with average diameters from 1.1 cm to 3.8 cm, and endoscopic resection had a shorter operation time than laparoscopic resection, but there were no significant differences in intraoperative blood loss, length of stay, postoperative complications, and postoperative recurrence rates between the two approaches.

CONCLUSIONS

Endoscopic resection is predominantly tried for gastric GISTs of relatively small size. It seems effective and safe for gastric GISTs <2 cm in average diameter, with relatively short operation times.

A modified endoscopic method for resection of gastric submucosal tumor

BACKGROUND AND OBJECTIVE

Endoscopic mucosa-sparing lateral dissection (EMSLD) was developed by our group, and is used to remove gastric submucosal tumor (SMT). This study aims to evaluate the feasibility and safety of this method.

METHODS

This retrospective study included 25 patients who underwent EMSLDs at an endoscopy center as a national key unit in china from October 2015 to July 2016. The main data collected were the size of the gastric SMT, its location and origin, en bloc resection rate, operating time, intraoperative and postoperative complications, hospitalization expense, hospital days, and follow-up after hospital discharge.

RESULTS

The mean (SD) size of the gastric SMTs was 18.3 (5.9) mm; 96% (24/25) of the tumors originated in the muscularis propria; and 64% (16/25) and 28% (7/25) were located in the gastric fundus and gastric body, respectively. The rate of en bloc resection was 96% (24/25), and the rate of intraoperative perforations due to endoscopic full-thickness resection was 48% (12/25). All wounds and perforations were effectively closed using endoscopic clips combined with the retained mucosa. The mean operative time was 74.2 (38.0) min. Delayed bleeding and perforation were not observed.

CONCLUSION

Endoscopic mucosa-sparing lateral dissection is safe and feasible for the removal of gastric SMTs. The wound can be effectively closed using the retained mucosa and endoscopic clips, even if perforation has occurred. EMSLD provides an alternative to the resection of gastric SMTs, especially for tumors with a risk of intraoperative perforation.

Efficacy of Endoscopic Submucosal Excavation for Gastrointestinal Stromal Tumors in the Cardia

OBJECTIVE

Our goal was to estimate the feasibility and efficacy of endoscopic submucosal excavation (ESE) for the treatment of gastrointestinal stromal tumors (GISTs) in the cardia.

MATERIALS AND METHODS

We analyzed the clinical data of 30 patients who were diagnosed with GISTs after ESE in the cardia at the Endoscopy Center of Renmin Hospital of Wuhan University (China) from June 2009 to 2015. We evaluated the operative and postoperative conditions and long-term follow-up of these patients.

RESULTS

The success rate and the complete resection rate were both 100%. The maximum diameter of the tumor ranged from 1.0 to 3.5 cm (2.2±0.2 cm). The operation time was 20 to 120 min (50±5 min). During ESE, bleeding occurred in all cases (100%) with a mean blood loss of 50 mL, and perforation in 6 (20%), including 2 full-thickness resections. GIST was confirmed by pathology in all cases. Follow-up included endoscopy at 1, 3, and 6 months, and at 1 year. At 1 month, ulcer was detected in 23 cases (76.67%), titanium clips remained in 17 cases (56.67%), and scar tissues were observed in the remainder. No recurrence was found with gastroscopy.

CONCLUSIONS

The cardia is a unique anatomic location for GISTs, which often requires complex surgeries prone to complications. ESE for GISTs of the cardia is a challenging, but safe and effective procedure.

Incidental gastrointestinal stromal tumor at a gastroscopic polypectomy specimen: A case report and review of literature

Although gastrointestinal stromal tumors (GISTs) comprise less than 1% of all gastrointestinal (GI) tract tumors, they are the most common mesenchymal tumors of the GI tract. Gastrointestinal stromal tumors can occur anywhere along the GI tract, but the stomach and small intestine are the most frequently involved sites. Gastrointestinal stromal tumors are frequently asymptomatic, and one-third of all cases are found incidentally. Endoscopy, endoscopic ultrasonography, and computed tomography are useful tools in the diagnosis. Endoscopic mucosal resection, endoscopic submucosal dissection, laparoscopic endoscopic cooperative surgery, and surgery with either laparoscopic or open approaches are treatment modalities for GISTs. An R0 resection is the principle surgery. Imatinib is the main medical agent used in the adjuvant or neoadjuvant treatment of GIST. We present a 65-year-old woman with an asymptomatic GIST that arose from a gastric polyp treated via endoscopic polypectomy.

Minimally invasive surgery for submucosal (subepithelial) tumors of the stomach

Minimally invasive surgery has become common in the surgical resection of gastrointestinal submucosal tumors (SMTs). The purpose of this article is to review recent trends in minimally invasive surgery for gastric SMTs. Although laparoscopic resection has been main stream of minimally invasive surgery for gastrointestinal SMTs, recent advances in endoscopic procedures now provide various treatment modalities for gastric SMTs. Moreover, investigators have developed several hybrid techniques that include the advantages of both laparoscopic and endoscopic procedure. In addition, several types of reduced port surgeries, modification of conventional laparoscopic procedures, have been recently applied to the surgical resection of SMTs. Meanwhile, robotic surgery for SMTs requires further evidence and improvement.

Advances in research of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, arising from the interstitial cells of Cajal (ICCs), primarily in the stomach and small intestine. The growth of most GISTs is driven by the mutations of genes encoding oncogenic receptor tyrosine kinase KIT or platelet derived growth factor receptor alpha (PDGFRα). The pathogenesis of GISTs may involve ICCs, microRNAs (miRNAs), signaling pathways, DNA methylation, and KIT or PDGFRα gene mutations. This article systematically describes the advances in research of GISTs in terms of clinical features, imaging characteristics, endoscopic features, histopathological features, diagnosis and therapies.

Clinicopathological characteristic and clinical handling of the patients with 2 cm or less gastric GISTs

BACKGROUND

We previously reported that safety and efficacy of mucosal cutting biopsy for diagnosing included 2 cm or less gastric GISTs. However, there have been no reports stating the clinicopathological characteristic and clinical handling of the patients with 2 cm or less gastric GISTs. The aim of our study is to investigate the clinicopathological characteristic and clinical handling of the patients with 2 cm or less gastric GISTs.

METHODS

The 19 patients diagnosed with GIST by mucosal cutting biopsy were divided into 2 groups: Group I; subjects were GISTs with 2 cm or less, Group II; subjects were GISTs >2 cm. We compared the 2 groups in terms of mean age, tumor size, tumor site, histopathological risk grade. In cases that underwent surgery with a diagnosis of GIST, we compared the pre- and postoperative histopathological diagnosis, and the histopathlogical risk grade within each group.

RESULTS

The mean age and tumor size were significantly higher in Group I than in Group II. Meanwhile, there were no significant differences between the 2 groups, sex ratio, tumor site. All lesions were at histopathological risk grade at very low risk and low risk respectively. In 17 patients with GIST who underwent surgery, the histopathological diagnoses, immunostaining were in agreement with those from the mucosal cutting biopsy specimens in all cases, but mitotic count of one patient was not in agreement in group II.

CONCLUSIONS

The 2 cm or less gastric GISTs diagnosed with histpathlogical very low risk can be considered acceptable to follow-up.

Surgical treatment of gastric gastrointestinal stromal tumor

Gastrointestinal stromal tumor is the most common mesenchymal tumor in the gastrointestinal tract and is most frequently developed in the stomach in the form of submucosal tumor. The incidence of gastric gastrointestinal stromal tumor is estimated to be as high as 25% of the population when all small and asymptomatic tumors are included. Because gastric gastrointestinal stromal tumor is not completely distinguished from other submucosal tumors, a surgical excisional biopsy is recommended for tumors >2 cm. The surgical principles of gastrointestinal stromal tumor are composed of an R0 resection with a normal mucosa margin, no systemic lymph node dissection, and avoidance of perforation, which results in peritoneal seeding even in cases with otherwise low risk profiles. Laparoscopic surgery has been indicated for gastrointestinal stromal tumors <5 cm, and the indication for laparoscopic surgery is expanded to larger tumors if the above mentioned surgical principles can be maintained. A simple exogastric resection and various transgastric resection techniques are used for gastrointestinal stromal tumors in favorable locations (the fundus, body, greater curvature side). For a lesion at the gastroesophageal junction in the posterior wall of the stomach, enucleation techniques have been tried preserve the organ's function. Those methods have a theoretical risk of seeding a ruptured tumor, but this risk has not been evaluated by well-designed clinical trials. While some clinical trials are still on-going, neoadjuvant imatinib is suggested when marginally unresectable or multiorgan resection is anticipated to reduce the extent of surgery and the chance of incomplete resection, rupture or bleeding.